Some Questions with gardening node (sensor/accurator)

[dakky]

Hello

Ich want to implement a gardening node and found this project:
http://iot-playground.com/blog/2-uncategorised/61-nrf24l01-arduino-balcony-irrigation-controller

I think i am able to adopt this for my setup without the solar power part.

There are still some question on the hardware-side:

• the pumps
  When using this setup: i need one pump per plant. Is there a more efficient setup with one pump and valves? I searched for valves, but they seem to be far more expensive that these cheap pumps?
• unknown parts on the pcb
  http://iot-playground.com/images/articles/029/20150620_135404x.jpg
  Can someone explain to me, what the items below the arduino are used for?
• Power
  when using a 12v power supply a can use it to power the pumps (directly), the 5v arduino (via the RAW input pin) and the radio (via the 5V pin of the arduino + a 3v regulator)? Is that correct? did i miss anything? Any idea, how many pumps should run at the same time? or should it be limited to one per time on the controller side?

Anything i should think about?

thank
Dakky